Vehicle occupant restraint belt retractors have heretofore been provided with winding prevention mechanisms for selectively relieving the tension on the belt to enhance comfort of the restrained occupant. U.S. Pat. No. 3,869,098 by Raymond G. Sprecher, issued Mar. 4, 1975, discloses a belt retractor in which actuation of the winding prevention feature occurs in response to a predetermined sequence of belt winding and unwinding movement. U.S. Pat. No. 4,153,274 by Lloyd W. Rogers et al, issued May 8, 1979, provides a winding prevention mechanism which is manually actuated.
It is characteristic of the winding prevention mechanisms of both the above-captioned patents that the winding prevention feature is cancelled in response to a predetermined extent of belt unwinding so that the winding effort of the wind-up spring is restored to pull the belt taut about the seated occupant. In a retractor having such a winding prevention mechanism, it is possible for the vehicle occupant to unbuckle the seat belt without having performed the belt unwinding motion necessary to cancel the winding prevention mechanism and the belt will not be retracted onto the reel. U.S. Pat. No. 3,973,786 by Lloyd W. Rogers, issued Aug. 10, 1976, provides an improvement wherein the winding prevention mechanism is automatically cancelled whenever the door is moved from the closed to the open position.